Positron facilities and positron research activities at RID and R3The Positron Centre Delft is a research facility established at the Delft University of Technology. It provides access to the equipment (as part of RID) and scientific expertise concentrated in the sections FAME and NPM2 of the department R3 of the faculty of Applied Science. The majority of the experimental Positron Annihilation (PA) techniques developed to this aim are based on the analysis of the annihilation radiation. They can be classified into two groups, which are distinguished by the positron’s sensitivity to the local electron density (positron lifetime, PALS) and to the local electron momentum distribution (Dopplerbroadening (PADB) and Angular Correlation (2D-ACAR)).